# keyword.py - keyword expansion for Mercurial
#
# Copyright 2007 Christian Ebert <blacktrash@gmx.net>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.
#
# $Id$
#
# Keyword expansion hack against the grain of a DSCM
#
# There are many good reasons why this is not needed in a distributed
# SCM, still it may be useful in very small projects based on single
# files (like LaTeX packages), that are mostly addressed to an audience
# not running a version control system.
#
# For in-depth discussion refer to
# <http://www.selenic.com/mercurial/wiki/index.cgi/KeywordPlan>.
#
# Keyword expansion is based on Mercurial's changeset template mappings.
# The extension provides an additional UTC-date filter ({date|utcdate}).
#
# The user has the choice either to create his own keywords and their
# expansions or to use the CVS-like default ones.
#
# Expansions spanning more than one line are truncated to their first line.
# Incremental expansion (like CVS' $Log$) is not supported.
#
# Binary files are not touched.
#
# Setup in hgrc:
#
#     # enable extension
#     keyword = /full/path/to/keyword.py
#     # or, if script in hgext folder:
#     # hgext.keyword =

'''keyword expansion in local repositories

This extension expands RCS/CVS-like or self-customized keywords in
the text files selected by your configuration.

Keywords are only expanded in local repositories and not logged by
Mercurial internally. The mechanism can be regarded as a convenience
for the current user and may be turned off anytime.

An additional date template filter {date|utcdate} is provided.

Caveat: "hg import" might fail if the patches were exported from a
repo with a different/no keyword setup, whereas "hg unbundle" is
safe.

Configuration is done in the [keyword] and [keywordmaps] sections of
hgrc files.

Example:
    [extensions]
    hgext.keyword =

    [keyword]
    # expand keywords in every python file,
    # except those matching "x*"
    **.py =
    x* = ignore

For [keywordmaps] demonstration run "hg kwdemo".
'''

from mercurial.i18n import gettext as _
from mercurial import commands, fancyopts, templater, util
from mercurial import cmdutil, context, filelog, localrepo
# findcmd might be in cmdutil or commands
# depending on mercurial version
if hasattr(cmdutil, 'findcmd'):
    findcmd = cmdutil.findcmd
else:
    findcmd = commands.findcmd
import os, re, shutil, sys, tempfile, time

deftemplates = {
    'Revision': '{node|short}',
    'Author': '{author|user}',
    'Date': '{date|utcdate}',
    'RCSFile': '{file|basename},v',
    'Source': '{root}/{file},v',
    'Id': '{file|basename},v {node|short} {date|utcdate} {author|user}',
    'Header': '{root}/{file},v {node|short} {date|utcdate} {author|user}',
}

nokwcommands = ('add', 'addremove', 'bundle', 'clone', 'copy', 'export',
                'incoming', 'outgoing', 'push', 'remove', 'rename', 'rollback')

def utcdate(date):
    '''Returns hgdate in cvs-like UTC format.'''
    return time.strftime('%Y/%m/%d %H:%M:%S', time.gmtime(date[0]))

def getcmd(ui):
    '''Returns current hg command.'''
    # commands.parse(ui, sys.argv[1:])[0] breaks "hg diff -r"
    try:
        args = fancyopts.fancyopts(sys.argv[1:], commands.globalopts, {})
    except fancyopts.getopt.GetoptError, inst:
        raise commands.ParseError(None, inst)
    if args:
        cmd = args[0]
        aliases, i = findcmd(ui, cmd)
        return aliases[0]

def keywordmatcher(ui, repo):
    '''Collects include/exclude filename patterns for expansion
    candidates of current configuration. Returns filename matching
    function if include patterns exist, None otherwise.'''
    inc, exc = [], ['.hg*']
    for pat, opt in ui.configitems('keyword'):
        if opt != 'ignore':
            inc.append(pat)
        else:
            exc.append(pat)
    if not inc:
        return None
    return util.matcher(repo.root, inc=inc, exc=exc)[1]

class kwtemplater(object):
    '''
    Sets up keyword templates, corresponding keyword regex, and
    provides keyword substitution functions.
    '''
    def __init__(self, ui, repo, path='', node=None):
        self.ui = ui
        self.repo = repo
        self.path = path
        self.node = node
        templates = dict(ui.configitems('keywordmaps'))
        if templates:
            # parse templates here for less overhead in kwsub matchfunc
            for k in templates.keys():
                templates[k] = templater.parsestring(templates[k],
                                                     quoted=False)
        self.templates = templates or deftemplates
        escaped = [re.escape(k) for k in self.templates.keys()]
        self.re_kw = re.compile(r'\$(%s)[^$]*?\$' % '|'.join(escaped))
        templater.common_filters['utcdate'] = utcdate
        try:
            self.t = cmdutil.changeset_templater(ui, repo, False, '', False)
        except TypeError:
            # depending on hg rev changeset_templater has extra "brinfo" arg
            self.t = cmdutil.changeset_templater(ui, repo,
                                                 False, None, '', False)

    def kwsub(self, mobj):
        '''Substitutes keyword using corresponding template.'''
        kw = mobj.group(1)
        self.t.use_template(self.templates[kw])
        self.ui.pushbuffer()
        self.t.show(changenode=self.node, root=self.repo.root, file=self.path)
        keywordsub = templater.firstline(self.ui.popbuffer())
        return '$%s: %s $' % (kw, keywordsub)

    def expand(self, node, data):
        '''Returns data with expanded keywords.'''
        if util.binary(data):
            return data
        c = context.filectx(self.repo, self.path, fileid=node)
        self.node = c.node()
        return self.re_kw.sub(self.kwsub, data)

    def shrink(self, text):
        '''Returns text with all keyword substitutions removed.'''
        if util.binary(text):
            return text
        return self.re_kw.sub(r'$\1$', text)

    def overwrite(self, candidates, mn):
        '''Overwrites candidates in working dir expanding keywords.'''
        files = []
        m = self.repo.manifest.read(mn)
        for f in candidates:
            data = self.repo.wread(f)
            if not util.binary(data):
                self.path = f
                data, kwct = self.re_kw.subn(self.kwsub, data)
                if kwct:
                    self.ui.debug(_('overwriting %s expanding keywords\n') % f)
                    self.repo.wwrite(f, data, m.flags(f))
                    files.append(f)
        if files:
            self.repo.dirstate.update(files, 'n')

class kwfilelog(filelog.filelog):
    '''
    Subclass of filelog to hook into its read, add, cmp methods.
    Keywords are "stored" unexpanded, and expanded on reading.
    '''
    def __init__(self, opener, path, kwtemplater):
        super(kwfilelog, self).__init__(opener, path)
        self.kwtemplater = kwtemplater

    def read(self, node):
        '''Substitutes keywords when reading filelog.'''
        data = super(kwfilelog, self).read(node)
        return self.kwtemplater.expand(node, data)

    def add(self, text, meta, tr, link, p1=None, p2=None):
        '''Removes keyword substitutions when adding to filelog.'''
        text = self.kwtemplater.shrink(text)
        return super(kwfilelog, self).add(text, meta, tr, link, p1=p1, p2=p2)

    def cmp(self, node, text):
        '''Removes keyword substitutions for comparison.'''
        text = self.kwtemplater.shrink(text)
        if self.renamed(node):
            t2 = super(kwfilelog, self).read(node)
            return t2 != text
        return super(kwfilelog, self).cmp(node, text)


def demo(ui, repo, **opts):
    '''print [keywordmaps] configuration and an expansion example
    '''
    msg = 'hg keyword config and expansion example'
    fn = 'demo.txt'
    tmpdir = tempfile.mkdtemp('', 'kwdemo.')
    ui.note(_('creating temporary repo at %s\n') % tmpdir)
    _repo = localrepo.localrepository(ui, path=tmpdir, create=True)
    _repo.ui.setconfig('keyword', fn, '')
    if opts['default']:
        kwstatus = 'default'
        kwmaps = deftemplates
    else:
        kwstatus = 'current'
        kwmaps = dict(ui.configitems('keywordmaps')) or deftemplates
    if ui.configitems('keywordmaps'):
        for k, v in kwmaps.items():
            _repo.ui.setconfig('keywordmaps', k, v)
    reposetup(_repo.ui, _repo)
    ui.status(_('config with %s keyword template maps:\n') % kwstatus)
    ui.write('[keyword]\n%s =\n[keywordmaps]\n' % fn)
    for k, v in kwmaps.items():
        ui.write('%s = %s\n' % (k, v))
    path = _repo.wjoin(fn)
    keywords = '$' + '$\n$'.join(kwmaps.keys()) + '$\n'
    _repo.wopener(fn, 'w').write(keywords)
    _repo.add([fn])
    ui.note(_('\n%s keywords written to %s:\n') % (kwstatus, path))
    ui.note(keywords)
    ui.note(_("\nhg --repository '%s' commit\n") % tmpdir)
    _repo.commit(text=msg)
    pathinfo = ('', ' in %s' % path)[ui.verbose]
    ui.status(_('\n%s keywords expanded%s:\n') % (kwstatus, pathinfo))
    ui.write(_repo.wread(fn))
    ui.debug(_('\nremoving temporary repo %s\n') % tmpdir)
    shutil.rmtree(tmpdir)


def reposetup(ui, repo):
    '''Sets up repo as kwrepo for keyword substitution.
    Overrides file method to return kwfilelog instead of filelog
    if file matches user configuration.
    Wraps commit to overwrite configured files with updated
    keyword substitutions.
    This is done for local repos only, and only if there are
    files configured at all for keyword substitution.'''

    if not repo.local() or getcmd(repo.ui) in nokwcommands:
        return

    kwfmatcher = keywordmatcher(ui, repo)
    if kwfmatcher is None:
        return

    # for backwards compatibility
    ui = repo.ui

    class kwrepo(repo.__class__):
        def file(self, f):
            if f[0] == '/':
                f = f[1:]
            if kwfmatcher(f):
                kwt = kwtemplater(ui, self, path=f)
                return kwfilelog(self.sopener, f, kwt)
            else:
                return filelog.filelog(self.sopener, f)

        def commit(self, files=None, text='', user=None, date=None,
                   match=util.always, force=False, lock=None, wlock=None,
                   force_editor=False, p1=None, p2=None, extra={}):
            wrelease = False
            if not wlock:
                wlock = self.wlock()
                wrelease = True
            try:
                removed = self.status(node1=p1, node2=p2, files=files,
                                      match=match, wlock=wlock)[2]

                node = super(kwrepo,
                             self).commit(files=files, text=text, user=user,
                                          date=date, match=match, force=force,
                                          lock=lock, wlock=wlock,
                                          force_editor=force_editor,
                                          p1=p1, p2=p2, extra=extra)
                if node is None:
                    return node

                cl = self.changelog.read(node)
                candidates = [f for f in cl[3] if kwfmatcher(f)
                              and f not in removed
                              and not os.path.islink(self.wjoin(f))]
                if candidates:
                    kwt = kwtemplater(ui, self, node=node)
                    kwt.overwrite(candidates, cl[0])
                return node
            finally:
                if wrelease:
                    wlock.release()

    repo.__class__ = kwrepo


cmdtable = {
    'kwdemo':
        (demo,
         [('d', 'default', None, _('use default keyword maps'))],
         _('hg kwdemo [-d]')),
}